The main purpose of the Pontiac parking brake cable has not changed over the years, but its application has. Today most vehicles are equipped with an automatic transmission that holds a vehicle in place when it is parked. In the past on cars equipped with a manual transmission the parking brake cables applies the tension on the rear braking system that held a vehicle in place. Because more Pontiac vehicles are being equipped with automatic transmissions, the need to engage the parking brake has diminished; thus reducing the number of time the parking brake is engaged and placing stress on the parking brake cables. Both past and present Pontiac models have always had a parking brake cables installed on them. Since they are rarely if ever used to help keep the vehicle still while it is parked, their usage is not part of a driver's typical routine. What most drivers should be aware of is just what other task this system can provide them. When the Pontiac parking brake cables have tension being applied to them, the rear brake shoes are engaged. This is in essence a manual braking system that can be deployed in case of an emergency. This emergency is if the hydraulic braking system on your Pontiac fails for any reason this manual system can be used to safely slow the vehicle down and prevent it from being in an accident. The only way this manual braking system can fail is if one of the parking brake cables snap. There are a total of three of these cables on all vehicles made. One from the passenger compartment that lead back toward a union and two that go from the union to the rear wheels.